Lighting can be an important consideration in some applications, such as livestock production. For example, incandescent or fluorescent lights may be turned on and off to simulate night and day for fowl living indoors. So-called “long day” lighting practices have been proposed to promote increased daily milk production from cows. Some research also suggests, for example, that poultry development behaviors can be influenced by lighting intensity, color, or time schedule. For example, infrared lighting may promote aggression in chickens, while too much darkness might lead to fearfulness.
In general, “poultry” can refer to domesticated fowl raised for meat or eggs. Typical examples of poultry can include chickens, turkeys, ducks, geese, emus, ostriches or game birds. In some cases, poultry are raised in a poultry house. An example poultry house could be 40 feet wide and 600 feet long, with a ceiling that is eleven feet high. For so-called “broilers,” young chickens raised for their meat, one research study found that a schedule of intermittent lighting resulted in decreased fat deposition and improved feed conversion efficiency relative to a continuous lighting environment. (See Rahmi, G., et al., “The Effect of Intermittent Lighting Schedule on Broiler Performance,” Int'l. J. Poultry Sci. 4 (6): 396-398 (2005)).
Various types of lighting have been employed in livestock production facilities. Livestock lighting systems that have been used include incandescent, fluorescent, and more recently, LEDs (light emitting diodes).
In general animal's perception of light involves photoreceptor cells that may be responsive to photons associated with light energy. Photoreceptors may be located in a retina. Photoreceptor cells may be of a rod or cone type. Some cones may be less sensitive to light than rod cells, but cones may allow perception of color.